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Earth’s Climate: Past, Present and Future Fall Term - OLLI West: week 2, 9/23/2014 Paul Belanger Earth's past climate history 1.Earth’s deep past before.

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Presentation on theme: "Earth’s Climate: Past, Present and Future Fall Term - OLLI West: week 2, 9/23/2014 Paul Belanger Earth's past climate history 1.Earth’s deep past before."— Presentation transcript:

1 Earth’s Climate: Past, Present and Future Fall Term - OLLI West: week 2, 9/23/2014 Paul Belanger Earth's past climate history 1.Earth’s deep past before the Cambrian (600 MaBP): hot and cold 2.Earth’s past: Cambrian onward: mostly hot-house Earth; 100s parts per million (ppm) 3.Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. 4.More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip 5.Today: 400 ppm and growing 2-3ppm/year

2 REVIEW OF WEEK 1 ITEM

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4 Video I showed at end of week 1 class – what is climate: – You tube link: https://www.youtube.com/watch?v=bjwmrg__ZVwhttps://www.youtube.com/watch?v=bjwmrg__ZVw Video I didn’t show – /don’t have time – see syllabus: – The climate system, feedbacks, cycles and self-regulation 1.6 – https://www.futurelearn.com/courses/climate-change-challenges- and-solutions/steps/3294/progress (7 mins) https://www.futurelearn.com/courses/climate-change-challenges- and-solutions/steps/3294/progress – an alternate: https://www.youtube.com/watch?v=lrPS2HiYVp8https://www.youtube.com/watch?v=lrPS2HiYVp8 – What factors determine Earth’s climate: – See IPCC-AR5 ( ) tab on my web page: – And this link from AR4 (2007) –

5 climate system - the inter-relationship and feedback of: Atmosphere Hydrosphere Biosphere Cryosphere Lithosphere ( weathering reduces CO2; volcanism increases it)

6 10 o C = (50 o F) 7.8 cc 20 o C = (68 o F) 15 cc 30 o C = (86 o F) 27.7 cc 40 o C = (104 o F) o C +1 o C = 8% increase in vapor

7 The CO 2 greenhouse gas effect is concentrated in the polar regions ! ! ! The large H 2 O greenhouse effect is controlled by temperature – H 2 O saturation doubles with every 10°C Increase As a result It is concentrated in the lower atmosphere of the tropics CO 2 is evenly distributed throughout the atmosphere Particularly in the Arctic ! The Earth and its atmosphere The most potent greenhouse gas is H 2 O - vapor

8 WEEK 2

9 1.Earth’s deep past before the Cambrian (600 MaBP): hot and cold 2.Earth’s past: Cambrian onward: mostly hot-house Earth; 100s parts per million (ppm) 3.Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. 4.More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip 5.Today: 400 ppm and growing Earth’s past climate

10 Earth’s deep past and early atmosphere before the Cambrian (600 MaBP): hot and cold Earth self regulates Tim Lenton video – 9 minute overview Article Link: BBC Nature h h You Tube – leaving for you to watch on your own: https://www.youtube.com/results?search_query=snow+bal l+earth – various links https://www.youtube.com/results?search_query=snow+bal l+earth Earth’s past climate

11 1.Earth’s deep past before the Cambrian (600 MaBP): hot and cold 2.Earth’s past: Cambrian onward: mostly hot-house Earth; 100s parts per million (ppm) 3.Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. 4.More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip 5.Today: 400 ppm and growing Earth’s past climate

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13 Climate Changes from Ocean Sediment Cores, since 5 Ma. Milankovitch Cycles 41K 100 K 3.0Ma 4.0Ma 2.0Ma 1.0Ma5.0Ma 0 When CO 2 levels get below ~ ppm Orbital parameters become more important than CO 2

14 1.Earth’s deep past before the Cambrian (600 MaBP): hot and cold 2.Earth’s past: Cambrian onward: mostly hot-house Earth; 100s parts per million (ppm) 3.Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. 4.More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip 5.Today: 400 ppm and growing Earth’s past climate

15 Scientific History of Climate change – PROXY DATA

16 Royer et al., 2003 Geologic cycles: Climate through the Phanerozoic: Carbon is the culprit Alternating Greenhouse Earth / Ice-house Earth

17 Cenozoic Deep Sea Climate Record Zachos et al hyperthermals Opening of the Drake passage isolating Antarctica and further drop in CO 2 Closing of Isthmus of Panama 41k-100k & amplitude change: Increase in Antarctic ice Azolla sequestering event

18 Correlation of CO 2 and temperature over last 65 million years Beerling and Royer, Nature 2011

19 Photosynthesis/Respiration CO 2 + H 2 0 ↔ CH 2 O + O 2 Weathering/Precipitation CO 2 + CaSiO 3 ↔ CaCO 3 + SiO 2 Long-term Carbon Cycle: rocks Two generalized reactions…

20 Berner, 2001 Long-term carbon cycle: rocks

21 50 million years ago (50 MYA) Earth was ice-free. Atmospheric CO 2 amount was of the order of 1000 ppm 50 MYA. Atmospheric CO 2 imbalance due to plate tectonics ~ ppm per year.

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23 1.Earth’s deep past before the Cambrian (600 MaBP): hot and cold 2.Earth’s past: Cambrian onward: mostly hot-house Earth; 100s parts per million (ppm) 3.Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. 4.More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip 5.Today: 400 ppm and growing Earth’s past climate

24 Climate Changes from Ocean Sediment Cores, since 5 Ma. Milankovitch Cycles 41K 100 K 3.0Ma 4.0Ma 2.0Ma 1.0Ma5.0Ma 0 When CO 2 levels get below ~ ppm Orbital parameters become more important than CO 2

25 1.Earth’s deep past before the Cambrian (600 MaBP): hot and cold 2.Earth’s past: Cambrian onward: mostly hot-house Earth; 100s parts per million (ppm) 3.Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. 4.More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip 5.Today: 400 ppm and growing Earth’s past climate

26 - SO – WHAT CONTROLS CLIMATE

27 Gerhard et al., 2001

28 Rohling, et al., (PALAESENS Project mbrs), o Forcings Solar Luminosity Atm. Comp. 2 o Forcings Continents (latitudes & elevations) Ocean circulation weathering CO 2 3 o Forcings Obliquity Precession Eccentricity CO 2 /CH 4 FEEDBACKS 4 o Forcings Volcanic eruptions Sunspots Cycles El Nino/ La Nina Cloud Solar storms

29 End of week 2 EXTRAS FOLLOW

30 Paleocene/Eocene Thermal Maximum PETM

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32 Wikipedia Proxy data: stable isotopes

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36 PETM - THE LAND RECORD

37 Bighorn Basin PETM interval in fluvial deposits with excellent alluvial paleosols - seen as color bands, which are soil horizons Found in Willwood Fm Reds, purples due to iron oxides in B horizons

38 Paleosol Density Pre-PETM PETM

39 Bighorn Basin Climate Plant fossils and isotopes show Mean Annual Temperature of 20 o to 25 o C or 68 to 77 o F Similar to Gulf Coast region today

40 PROXY DATA-EXTRAS

41 FROM CSI TO GSI: GEOLOGICAL SAMPLE INVESTIGATION LET THE EVIDENCE SPEAK FOR ITSELF

42 WE CALL THIS EVIDENCE “PROXY” DATA

43 Strandlines/shorelines Moraines Till Kettle lakes, etc. SOME OF THE EARLIEST PROXY DATA WAS FROM TERRESTRIAL DEPOSITS We may know what caused these today, but imagine back then?

44 IT’S THE INTERPRETATION THAT’S NOT ALWAYS CORRECT Darwin observed ancient Alpine shorelines: interpreted as ocean shoreline Agassiz – later correctly interpreted as ice- dammed lake-shore strandlines/shoreline

45 Jean Louis R. Agassiz “Father” of Glaciology Paleontologist Glaciologist

46 Photographic proxy data/evidence Ruddiman, 2008

47 EARLY PROXY DATA: TREE RINGS

48 Pollen & Lake core data Ruddiman, 2008

49 PROXY DATA: POLLEN DATA

50 PROXY DATA: LEAVES

51 Tree rings, corals, ice cores Ruddiman, 2008

52 PROXY DATA: ICE CORES

53 TERRESTRIAL DATA North American: Wisconsin Illinoian Kansan Nebraskan European: Wurm Riss Mindel Gunz

54 LATER EVIDENCE CAME FROM THE MARINE RECORD NOT WITHOUT IT’S PROBLEMS, BUT MORE COMPLETE

55 Cesare Emilani: Paleontologist, Chemist Father of Paleoceanography

56 Other Paleoceanographers Wally Broecker Thermal-haline “conveyor” belt of circulation

57 Bill Ruddiman Nick Shackleton Other Paleoceanographers

58 John Imbrie: CLIMAP

59 PROXY DATA: CORE DATA

60 PROXY DATA: BENTHIC FORAMS

61 PROXY DATA: PLANKTONIC FORAMS

62 Deep Sea Coring Ruddiman, 2008


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